Doppler estimation and timing synchronization of underwater acoustic communication based on hyperbolic frequency modulation signal

In underwater acoustic communications, Doppler effect should be described by Doppler scale which adversely affects the performance of the communication system. This paper presents a method by employing the hyperbolic frequency modulation (HFM) signal as a channel probe to make Doppler estimation and timing synchronization simultaneously. The Doppler compensation is realized by linear interpolation. A contrast with the linear frequency modulation (LFM) signal adopted in the conventional design is also made. Simulation results show that the method based on HFM signal has better estimation and more accurate timing synchronization performance. In addition, a sea-trial to test the method in this paper has been conducted and the results are presented to demonstrate the feasibility of the method.